1. Field of the Invention
The present invention pertains to flexible sign panels and in particular to such sign panels which are rolled up for compact storage.
2. Description of Related Art
Temporary highway signs warning motorists of roadside work activities have been employed for some time. It is common today, for warning sign systems to be considered in the early stages of planning a roadside improvement. With higher rates of speed and increased volume of traffic, a need for more advanced warning of temporary worksite conditions has been recognized. The implemetation of large numbers of signs of increased visibility and which are easy to deploy would aid in this regard.
Improvements to temporary warning signs have been realized by providing flexible message panels, typically make of a flexible fabric, such as plastic mesh material made of polyethylene or vinyl plastics. Over the years, these types of panels were improved with the addition of fluorescent materials to increase their ability to reflect light from oncoming vehicles. Commonly, reinforcing ribs or struts are used to maintain the flexible panels in a flat message-displaying condition. Ribs of glass fiber composition have been a popular choice for suspending flexible message panels. However, light weight metal tubing has also been a popular choice for displaying flexible message panels, and collapsible supporting systems have been proposed in commonly assigned U.S. Pat. No. 4,694,601.
Flexible sign panels must be stretched taut to maintain a flat position. Wind gusts and traffic induced wind bursts put substantial strain on a flexible sign panel, particularly at its points of support. Accordingly, various arrangements for joining supporting ribs to a flexible message panel have been proposed. For example, fabric pockets have been employed in U.S. Pat. Nos. 3,899,843 and 3,526,200, while resilient straps have been proposed in U.S. Pat. No. 4,592,158. As an alternative solution, rigid panel pockets have been proposed in U.S. Pat. Nos. 4,426,800 and 4,490,934. However, improvements are still being sought to provide a more compact storage of flexible message panel systems.